Skimming tool

ABSTRACT

A skimming tool  1  for smoothing and levelling wet plaster applied to a surface comprising: an elongate generally rectangular, flat, flexible, elastomeric web  2  and an elongate, substantially rigid handle  3  connected to and extending along substantially the length of one long edge of the web, wherein the handle is adapted to be gripped by the user

The invention relates to a “ruling off” skimming tool for smoothing andlevelling wet finish coat plaster applied to a surface such as a wall orceiling.

Conventionally, plaster is applied to walls and ceilings using a plastertrowel which comprises a flat rectangular stainless steel sheet havingdimensions of about 280 mm to 460 mm by 120 mm with a generallycylindrical handle mounted spaced from and parallel to the sheet. Thesame tool is used for smoothing and levelling the plaster once it hasbeen applied.

A known plaster “ruling off” levelling tool, known as a ‘Darby’,comprises an extruded aluminium elongate body which may be hollow orsolid. The known tool sometimes has a pair of spaced handles extendingperpendicularly there from. The spacing of the handles is adjustable insome cases. However, the ‘Darby’ tool, being generally rigid andinflexible, is only useful for “ruling off” and levelling backingplaster (first coat plaster) or scratch coat sand and cement render(first coat render).

The invention provides a new long tool for skimming, Smoothing andlevelling finish coat plaster (final coat plaster) reducing finishplastering times by approximately 75%. The new tool can make it possiblefor a single operative to tackle larger areas within short dryingtimes/conditions due to the advantage of the increase speed. In additionanother advantage of the tool is that levelling off of finish plaster onuneven substrates becomes possible giving an improved finish oversubstantially shorter and inflexible conventional stainless steel sheettrowels.

The invention provides a skimming tool for smoothing and levelling wetfinish coat plaster applied to a surface comprising: an elongategenerally rectangular, flat, flexible, elastomeric web and an elongate,substantially rigid handle connected to and extending alongsubstantially the length of one long edge of the web, wherein the handleis adapted to be gripped by the user at any point along its length.

Embodiments of the inventions are described below with reference to theaccompanying drawings, in which:

FIG. 1 is a perspective view, from above, of a skimming tool;

FIG. 2 is a perspective view, from above, showing a short end portion ofthe tool;

FIG. 3 is a perspective view, from below, showing a short end portion ofthe tool;

FIG. 4 is an end view of the tool;

FIG. 5 is a perspective view, from above, of an end portion of the toolwith an end cap in place;

FIG. 6 is an enlarged fragmentary view showing a portion of the blade ofthe tool;

FIG. 7 is an end view of a second embodiment of the tool;

FIGS. 8 and 9 show details of portions of the second embodiment;

FIG. 10 shows an end portion of the handle of the second embodiment; and

FIG. 11 is a plan view of a third embodiment.

The drawings show a long skimming tool 1 for smoothing and levellingfinish coat plaster applied to a surface such as a wall or a ceiling.The tool comprises a plaster engaging blade in the form of an elongate,generally rectangular, flat, flexible, elastomeric web 2 which is joinedto a substantially rigid, elongate handle 3 which extends alongsubstantially the entire length of one long edge of the web. The handle3 has a cross-sectional profile which is substantially constant alongits length and is thereby adapted to be gripped by the user at any pointalong its length.

In the preferred embodiments, the web 2 and handle 3 have a length of600 mm to 1500 mm, preferably about 1200 mm and the operative width ofthe web is 70 to 100 mm, preferably about 90 mm. If the operative widthis less than about 70 mm, the tool becomes too rigid and inflexible. Atool having a length shorter than 600 mm may be useful but if the lengthis much shorter than that, some benefits of the tool are lost. A longertool may be provided but only up to about 1800 mm is practicable formost users although tools of up to 2000 mm or even longer may bepracticable for some users. In the preferred embodiments, the web 2 isan extrusion formed of a rigid or semi rigid PVC and has a thickness ofbetween 1.0 and 3.0 mm, preferably about 1.7 mm. This gives the websufficient stiffness and flexibility to operate efficiently.

The handle 3 is a hollow extrusion formed of aluminium and issubstantially rigid. The handle has a generally rectangular profilecomprising a first side 4 which is generally co-planar with the web, asecond side 5, generally perpendicular to the web, a third side 6parallel to the first side and a fourth side 7 parallel to the secondside. The second side 5 is formed in an S profile providing a curvedrecess 8 extending along the handle and adapted to receive thefingertips of the user. The ergonomic design of the handle allows it tobe comfortably gripped by the user at all times and especially whenskimming overhead.

The handle 3 is provided with a bifurcated flange 9 at the junctionbetween the first and second sides 4, 5 of the handle and extendinggenerally in the plane of the web 2. The limbs 10 and 11 of the flangedefine a recess 12 in the form of a channel which extends along thelength of the handle. The recess receives and holds the edge portion 13of the web. Shoulders 14, 15 are formed on the web to abut the ends ofthe limbs 10 and 11. In the embodiment of FIGS. 1 to 6, the recess 12receives the edge portion 13 as a snap fit by virtue of barbedformations in the recess and on the portion 13.

The lower surface of the web, which is the operative surface whichengages the plaster being smoothed, is formed with a plurality ofparallel grooves 18 extending along the length thereof and definingparallel ridges 16 therebetween. The ridges 16 and the flat grooves 18therebetween are best seen in FIG. 6. This ridged surface helps to holdonto the plaster/material and distribute it evenly across peaks andtroughs in the uneven substrate surface, thus facilitating an improvedflatter finish. In addition the ridges also hold the surplus plaster onthe tool during the operation preventing mess and spillage. The seriesof ridges along the surface strengthen the web but allow a slenderprofile and flexibility.

The hollow body of the handle is closed by end caps 17 as shown in FIGS.5, 10 and 11.

FIGS. 7 to 11 show some further embodiments, which, except as discussed,are the same as the embodiment of FIGS. 1 to 6.

FIGS. 8 and 9 show a detailed cross-section through part of the handleand web of a second embodiment. In this embodiment, the handle is formedwith a bifurcated flange 9, as before, with limbs 10 and 11 which definethe recess 12. In this embodiment, the edge portion 13 of the web isreceived and held in the recess in a slack fit having a nominalclearance all round the edge portion 13 of about 0.125 mm at about 20°C. The edge portion 13 has an enlarged section 20 running therealongwhich is held in a complimentary enlarged section 21 of the recess. Theenlarged sections of the web and the recess are in the form of a balland socket when viewed in cross-section. The shapes and dimensions ofthe web and recess, and in particular, the loose or slack fit, permitsliding movement of the edge portion 13 of the web along the length ofthe recess but prevent movement of the web out of the recess in thedirection perpendicular to the length of the recess indicated by arrow Ain FIG. 7. In this embodiment, the direction A lies in the plane of theweb. In this embodiment, the web is fitted to the handle by sliding theedge portion 13 of the web into and along the recess 12 on the handle.

The loose or slack fit of the edge of the web in the handle servesvarious functions. Firstly, it allows the web to expand differentiallyto the linear expansion of the handle. This is especially importantwhere the handle and web are made of different materials since withoutthis facility the web might expand more than the handle under ambientconditions. If the web is held rigidly in the handle, it may tend tokink or buckle along its length making it difficult or impossible to usecorrectly. Secondly, this arrangement enables simple replacement of aworn or damaged web into a handle. Other web profiles of rigid orsemi-rigid design may be introduced for other different tasks to beperformed.

FIG. 10 shows an end portion of the handle with an end cap 17 which is apush fit into the open end of a hollow extruded handle and is retainedby catches 23 snapping into apertures 24. The end cap has an opening 25which permits drainage of water from within the hollow handle. A portionof the end cap overlies the open end of the recess 12 to retain the webin place.

FIG. 11 shows a tool in which the end caps are held in place by selftapping screws 26 which are screwed into the open ends of the enlargedsection 21 of the recess 12. The end sections of the web have cut awayportions 27 which prevent engagement with the screw. The length of theweb is selected such that it can expand more than the handle withoutengaging the screws or the end caps.

In an alternative construction (not shown) the handle and web may beformed of a single plastic extrusion formed of a single material,preferably PVC. In another alternative, the handle and web may be madeof different plastic materials, or simply of differently colouredplastic materials blending together at a join along the length of thetool.

In a yet further embodiment (not shown) the handle can be solid and madefrom wood or other suitable material. In this embodiment the web may beextended to overlie the first side of the handle and be glued orotherwise fixed thereto.

1. A skimming tool for smoothing and levelling wet finish coat plaster applied to a surface, comprising: a plaster engaging blade comprising an elongate generally rectangular, flat, flexible, elastomeric web having a proximal edge portion and a distal edge portion, and an enlarged section at the proximal edge portion of the web; and an elongate, substantially rigid handle configured to connect to the plaster engaging blade, wherein the handle is adapted to be gripped by a user at any point along a length of the handle, wherein the handle defines a recess extending along the length of the handle, and wherein the recess comprises a channel and an enlarged section, the channel having a first height adjacent the enlarged section and the enlarged section having a second height greater than the first height; wherein, when the handle is connected to the plaster engaging blade: the enlarged section of the plaster engaging blade is received in the enlarged section of the recess in the handle with a slack fit that permits sliding movement of the plaster engaging blade in a direction parallel to a length of the recess but prevents movement of the plaster engaging blade in a direction perpendicular to the length of the recess; the proximal edge portion of the web is received in the channel; and the web extends outwardly from the handle and the distal edge portion of the web is spaced apart from the handle. 2-3. (canceled)
 4. A skimming tool as claimed in claim 1, wherein the enlarged sections of the web and the recess are in the form of a ball and socket in cross-section.
 5. A skimming tool as in claim 1, wherein the handle has a generally rectangular profile comprising a first side generally parallel with the web and a second side generally perpendicular to the web and being formed with a curved recess therealong adapted to receive the fingertips of the user.
 6. A skimming tool as in claim 1, wherein the handle is hollow and wherein the skimming tool further comprises removable end caps configured to close off opposite ends of the handle.
 7. A skimming tool as claimed in claim 6, wherein the end caps, when in place, overlie opposite open ends of the recess to prevent lengthwise movement of the plaster engaging blade out of the recess.
 8. A skimming tool as claimed in claim 1, wherein the handle and the web are formed by extrusion.
 9. A skimming tool as claimed in claim 1, wherein the handle is formed of aluminum and the web is formed of PVC.
 10. A skimming tool as claimed in claim 1 wherein the web and the handle both have a length greater than about 600 mm.
 11. A skimming tool as claimed in claim 10, wherein the web and the handle have a length of 600 mm to 1500 mm.
 12. A skimming tool as claimed in claim 11, wherein the web and the handle have a length of about 1200 mm.
 13. A skimming tool according to claim 1, wherein an operative surface of the web comprises a plurality of parallel ridges extending along a length of the web and located proximate the distal edge portion of the web.
 14. (canceled)
 15. A skimming tool as claimed in claim 1, wherein the web comprises a first material having a first coefficient of thermal expansion and the handle comprises a second material having a second coefficient of thermal expansion less than the first coefficient of thermal expansion.
 16. A skimming tool as claimed in claim 1, wherein the handle further comprises a bifurcated flange defining the channel, the bifurcated flange comprising a first limb and a second limb spaced apart from the first limb.
 17. A skimming tool as claimed in claim 16, wherein the plaster engaging blade further comprises a first shoulder extending from a first side of the web and a second shoulder extending from a second side of the web, and wherein when the handle is connected to the plaster engaging blade, the first and second shoulders abut distal ends of the first and second limbs.
 18. A skimming tool as claimed in claim 17, wherein the first limb has a first width and the second limb has a second width smaller than the first width, and wherein the first shoulder is spaced apart from the proximal edge portion of the web by a first distance and the second shoulder is spaced apart from the proximal edge portion of the web by a second distance less than the first distance.
 19. A skimming tool as claimed in claim 1, wherein the handle extends along substantially the length of the proximal edge portion of the web.
 20. A skimming tool as claimed in claim 1, wherein the enlarged section of the recess is located at a proximal-most end of the recess.
 21. A skimming tool as claimed in claim 20, wherein, when the handle is connected to the plaster engaging blade, a substantially constant nominal clearance is defined extending around the proximal edge portion of the web and the enlarged section of the blade. 